Old growth, regrowth, and planted woodland provide complementary habitat for threatened woodland birds on farms

Abstract

A central challenge for threatened species conservation in agricultural landscapes is to understand the relative contributions of old growth, regrowth, and planted woodland to species persistence. We offer a new perspective into solving this problem by using a systematic conservation planning approach to integrate spatial biodiversity and economic information with patch complementarity. We applied this to an eight-year study of woodland birds vulnerable to extinction across an extensive agricultural region of Australia. We used regression and ordination analyses to show that species were more likely to occur in regrowth and old growth woodland patches compared with plantings. We then set objectives of finding sets of complementary patches for supporting species across the landscape, and explored biodiversity trade-offs resulting from production-or cost-focused objectives. We found that species persistence could be achieved only through sets of patches containing all patch types (old growth, regrowth, plantings). Scenarios that selected sets of patches irrespective of patch type maximized species occurrence over time for the lowest combined area and establishment costs. Patch sets had a higher proportion of plantings for the objective of minimizing area, but a more equal proportion of patch types for the objective of minimizing cost. Our findings demonstrate what the relative composition of old growth, regrowth, and plantings should be when considering vegetation management interventions for threatened species conservation. Government policy and associated funding aimed at improving biodiversity conservation in agricultural landscapes needs to promote both regrowth woodland and revegetation planting strategies in addition to old growth woodland protection.

Weather effects on birds of different size are mediated by long‐term climate and vegetation type in endangered temperate woodlands

“…Third, our findings suggest that restoration plantings, regrowth woodlands, and old-growth woodlands act as different habitats for birds, with the responses varying as a function of body size, long-term climate, and short-term weather. This underscores the proposition that a diversity of structural vegetation types is needed to maximize the array of bird species that persist within woodland environments in landscapes dominated by agriculture (Ikin, Tulloch, Ansell, & Lindenmayer, 2018). However, there are some important nuances beyond the collective value of these vegetation assets.…”

Ongoing declines of woodland birds: Are restoration plantings making a difference?

“…The value of small habitat patches for biodiversity conservation has been well documented and reviewed (Fischer and Lindenmayer 2002 b , Tulloch et al 2016, Lindenmayer 2019, Wintle et al 2019). Restoration plantings provide habitat that is complementary to existing woodland remnants (Ikin et al 2018), and in which birds can breed successfully (Belder et al 2020 b ). There is no doubt that restoration plantings are a necessary conservation strategy in fragmented agricultural landscapes.…”

“…We predicted that survival and site fidelity in restoration plantings would be high, as we have 20 yr of survey data in our study region suggesting that woodland birds readily occupy restoration plantings (Lindenmayer et al 2018). We expected that birds in woodland remnants would show even higher survival and site fidelity, as these patches are typically considered to support a wider range of species than restoration plantings (Cunningham et al 2008, Ikin et al 2018). In addition, most of the species chosen for our study are sedentary, and long‐distance movements are not commonly reported (Australian Bird and Bat Banding Scheme 2016).…”

Revegetation and reproduction: do restoration plantings in agricultural landscapes support breeding populations of woodland birds?

“…Some species of conservation concern, such as the brown treecreeper (Climacteris picumnus), rely on habitat features that are present in woodland remnants but take decades to develop in restoration plantings (Vesk et al 2008). It is for this reason that restoration plantings should be considered complementary to, and not a replacement for, remnant woodland (Cunningham et al 2008;Lindenmayer et al 2018d;Ikin et al 2018).…”

“…Studies examining woodland bird responses to restoration plantings typically use pattern data such as presence and abundance to infer habitat quality. Previous research has offered insights into colonisation and extinction patterns (Barrett et al 2008;Mortelliti and Lindenmayer 2015), changes in bird community composition in plantings over time (Mac Nally 2008;Lindenmayer et al 2016Lindenmayer et al , 2018cDebus et al 2017), and occupancy trends relating to site type, habitat structure, and composition (Martin et al 2011;Munro et al 2011;Ikin et al 2018). However, do patch attributes have the same influence on breeding success as they do on site occupancy?…”